Some parts of the Adelaide beaches are experiencing significant sand loss and erosion of the sand dune system.
The sand along Adelaide’s coast naturally moves northward, by the wind and waves. This causes sand to build up on our northern beaches such as Semaphore, and causes sand loss and erosion along our southern and central coast such as West Beach and Henley Beach South.
The State Government manages the metropolitan coastline to enable the community to enjoy sandy beaches. Works to move sand has occurred across the metropolitan beach system for nearly 50 years.
West Beach has had serious and ongoing erosion for a number of years. At present, beach levels at West Beach and Henley Beach South are lower than at any other time since records began.
From Henley Beach to the north, the beaches are generally in good condition as the sand lost from southern beaches drifts north.
Sand continues to accumulate in Largs Bay, with wide dunes from around the Semaphore jetty northwards.
The beaches in the southern part of the coast (from Glenelg to Kingston Park) are generally stable because of successful beach management. The pipeline from Glenelg to Kingston Park currently pumps approximately 100,000 cubic metres (m3) of sand successfully each year.
Read an arti cle from InDaily ‘ Shifting sands – why SA pays for an endless cycle of beach replenishment’.
Watch a recordin g of a webinar, ' The history of Adelaide's beaches' featuring author and leading coastal expert Professor Andy Short.
The erosion at West Beach has had a number of impacts. Immediately north of the boat harbour the dunes have receded many metres, relying on regular recycling of sand from further north to manage the erosion.
Further north, the beach at the West Beach Surf Life Saving club has been mostly eroded and the clubhouse, coast park and car park rely on a seawall for protection.
At the northern end of the seawall, the erosion has lowered the beach so that the beach access ramp is sometimes closed. The loss of dunes in this area has placed assets at risk, and is requiring regular replenishment to maintain protection levels.
The erosion has progressed to affect Henley Beach South, with much of the sand dunes in front of the seawall being affected.
In 2017, a coastal processes modelling study was commissioned by the Department for Environment and Water, the Coast Protection Board, the City of Charles Sturt and West Beach Parks to better understand the coastal processes at West Beach and to examine alternative management options. This was needed because of the ongoing loss of sand each year at West Beach.
External consultants DHI completed a
report in 2018.
The research undertaken by DHI has shown that the sand loss at West Beach (the section of coastline running north from the West Beach boat harbor at West Beach Parks to the Torrens Outlet) is significant, and greater than previously estimated.
The report made it clear that even if current management activities were maintained, erosion will continue around West Beach and Henley Beach South, and progressively move north.
The report tested out three alternative scenarios for managing the beach and dune erosion at West Beach, with their results modelled. All three options involve beach replenishment, and varied by bringing in differing amounts of sand over different timescales.
Feedback from local government, industry and community stakeholders, together with the best available research and modelling has been taken into consideration in final decision making.
During the course of the study, the scope was amended to expand the analysis of beach profiles along the entire system from Kingston Park to Largs Bay, to enable a better understanding of the influence of management of adjacent beaches on West Beach and vice versa. This expanded analysis also provides insight into the management of the entire Adelaide beach system.
The state government has committed $48.4 million to the
Securing the future of our coastline project. This project will:
sand recycling pipeline from Semaphore to West Beach to move sand from beaches where it builds up.
Deliver a large quantity of sand (500,000 cubic metres) to West Beach from outside of Adelaide’s beach system to make up for losses that have occurred since the late 1990s.
Restore sand dunes using best practice techniques and native plants in partnership with local councils and coastal community groups.
The beach replenishment will put sand on our most vulnerable and eroded beaches including West Beach and Henley Beach South, with benefits to other beaches as sand naturally moves northward.
Before the pipeline is built and the external sand is delivered, sand needs to be
moved by truck from Semaphore to protect West Beach in the interim (spring and autumn 2021–21).
The announcement has been informed by
completed in 2018 by external consultants DHI on behalf of the Department for Environment and Water, the Coast Protection Board, the City of Charles Sturt and West Beach Parks. research
In 2019–20 and 2020–21, beach replenishment to West Beach and Henley Beach South will match current rates of loss and stabilise and maintain the beaches and dunes in the short term.
Then in 2021–22, a large scale replenishment using sand from an external source (outside of the Adelaide beach system) is planned to be delivered. This will raise the beach levels and boost sand dune buffers at West Beach and Henley Beach South with benefits to other beaches as sand moves northward.
Following the project planning phase (including detailed designs, engineering, community consultation and approvals), the pipeline is planned for construction in 2021–22, with the pipeline operational by end 2022–23.
The department is working closely with a community reference group on the project.
Watch the video to learn more about how we manage Adelaide’s beaches
The Semaphore South breakwater (pictured at the far end of the beach in photo) is the primary source of sand to replenish Adelaide’s eroding southern beaches.
Sand is also being moved from the beach between the Semaphore and Largs Bay jetties. This photo was taken two weeks after sand was collected in November 2019.
Management of the entire metropolitan coast needs to be adaptive and flexible. Our beaches are constantly changing and sand is naturally moved northward by the wind and waves, which causes sand to build up on our northern beaches, such as Semaphore, but causes erosion along our southern and central coast such as Seacliff, Brighton and Henley Beach.
A sustainable approach to managing our beaches involves recycling sand from areas of where sand builds up to areas of loss. Investigations have taken place to see if sand in other northern beaches is suitable to use for beach replenishment while the pipeline is built and before sand from an external source is available.
The West Beach area has been eroding since the 1960s and has received many hundreds of thousands of cubic metres of sand to manage the area over the years.
When beaches are replenished with sand it is normal for some of it to be washed away during the next storm. If the replenishment sand wasn’t there, then West Beach would be even more eroded and exposed.
Much of the sand that is washed offshore during storms is moved back onshore during calmer periods, so it is not wasted. This sand will also help maintain beaches as it drifts naturally to the north.
Adding sand to the Adelaide beach system benefits more than just West Beach, it also ensures there is more sand to flow between the beaches and be recycled.
Why aren't structures like groynes built to try to reduce the natural drift of sand northward?
Structures of the size required to have an impact are very expensive to construct. These areas would then require large volumes of sand to be brought in from an external source to “pre-fill” them. This pre-filling with external sand is essential otherwise the coast to the north of each structure would be eroded.
In addition, the experience with structures on the Adelaide coast and elsewhere in South Australia is they also trap large quantities of beach-cast seagrass, which has an impact on the usability of the beaches and increases management costs.
When factoring in these aspects, the sustainable approach to managing our beaches involves recycling sand from areas where sand builds up to areas of loss. This means the protection of Adelaide’s beaches can be achieved without negative impacts from structures, which would tend to interrupt our long sandy beaches.
By building a structure or structures like groynes and breakwaters that slow sand movement along the coast, the area in the vicinity of the trapped sand can be protected. However, the coast to the north (down-drift) of the structure will then be starved of sand unless the area is replenished.
An example of the use of structures along the beach in Japan.
Options involving the construction of hard engineering structures to re-orientate the West Beach shoreline were considered by DHI and included offshore breakwaters and headland control structures. A range of risks and disadvantages were identified with these options. The DHI report does not model any management options that use structures to retain sand on the beaches.
During the 1980s and 1990s, the Seacliff and Brighton coast was suffering from severe erosion that threatened the foreshore. To address this, a large scale beach replenishment with sand sourced externally was undertaken.
During the 1990s over 1 million cubic metres of sand was dredged from sand deposits offshore of Port Stanvac and delivered to that section of the coast, which formed and stabilised the dunes and in turn helped to stabilise the beach.
The operation of the sand recycling pipeline from 2013 onwards has maintained sand volumes and further stabilised this part of the coast and will continue to do so as required.
Local councils play a critical role in protecting regional assets from coastal hazards and maintaining coastal areas for all South Australians and tourists. The state government has committed an additional
$4 million over 4 years to regional coasts to repair, restore and sustain them in partnership with local councils. This support responds to the increasing demand for coastal protection infrastructure to address hazards like flooding and erosion.
The program is open to councils with a particular focus on the outer metro and regional areas.
. Learn more
Beach management strategies vary across Australia and internationally due to differences in coastal processes, climate and landscape. The approach for managing Adelaide’ beaches is based on expert advice underpinned by decades of data collected, review and assessment of methods used around the world, consideration of the issues specific to Adelaide’s beaches, and including current and historical survey information on beach profiles and independent technical reports.
Works to restore eroded dunes at Semaphore South has recently been completed. Find out more about the restoration.
For enquiries contact the Department for Environment and Water on 8124 4928 or email
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